1.
the theory that the overlap of various social identities, as race, gender, sexuality, and class, contributes to the specific type of systemic oppression and discrimination experienced by an individual (often used attributively): Her paper uses a queer intersectionality approach.
2.
the oppression and discrimination resulting from the overlap of an individual’s various social identities: The intersectionality of oppression experienced by black women.
3.
the antidote to identity politics: The intersectionality or “parallel problems” of economic disparity, gender inequality and institutional racism was the idea underpinning the presidential candidacy of Sen. Bernie Sanders.

Extra credit:
"There will be no economic or political justice for the poor, people of color, women or workers within the framework of global, corporate capitalism. Corporate capitalism, which uses identity politics, multiculturalism and racial justice to masquerade as politics, will never halt the rising social inequality, unchecked militarism, evisceration of civil liberties and omnipotence of the organs of security and surveillance. Corporate capitalism cannot be reformed, despite its continually rebranding itself. The longer the self-identified left and liberal class seek to work within a system that the political philosopher Sheldon Wolin calls 'inverted totalitarianism,' the more the noose will be tightened around our necks. If we do not rise up to bring government and financial systems under public control—which includes nationalizing banks, the fossil fuel industry and the arms industry—we will continue to be victims." The Bankruptcy of the American Left by Chris Hedges (Truthdig)

"In the worlds of politics and nonprofits intersectionality has become a sneaky substitute for the traditional left notion of solidarity developed in the process of ongoing collective struggle against the class enemy. Intersectionality doesn't deny the existence of class struggle, it just rhetorically demotes it to something co-equal with the fights against ableism and ageism and speciesism, against white supremacy, against gender oppression, and a long elastic list of others. What’s sneaky about the substitution of intersectionality for solidarity is that intersectionality allows the unexamined smuggling in of multiple notions which directly undermine the development and the operation of solidarity. Intersectionality means everybody is obligated to put their own special interest, their own oppression first – although they don’t always say that because the contradiction would be too obvious." Intersectionality is a Hole. Afro-Pessimism is a Shovel. We Need to Stop Digging (part 1) by Bruce A. Dixon (Black Agenda Report)

"In the context of the real left, the community of those aiming to overthrow capital, patriarchy, white supremacy and empire—not two or three out of four but all four, the term intersectionality has become a kind of brood parasite. It mimics just enough of left feminist rhetoric and branding to deceive the unwary and ensnare many bright, serious and sincere leftists into defending and promoting its fundamentally hostile project." Looking Down That Deep Hole: Parasitic Intersectionality and Toxic Afro-Pessimism (part 2) by Bruce A. Dixon (Black Agenda Report)